Piston expanding tool



June 4, 1940. s. F. OLIVER rxs'ron EXPANDING 001.

2 Shets-Sheet 1 Filed April 25, 1939 JAZIZZE'NTCJR 7 SHEFFIEL R OZZIYE'R BY W PIEnEl- Jung 4, 1940. 5 F. OI IVER 2,203,175

PISTON EXPANDING TQQL Filed April 25, 1939 2 Sheets-Sheet 2 $4 I f I g I I g H i 60 f' 5 12 ii 0 o 1N YEN TOR 0 SH 'FFJEL F. OLIVER .B Y j AT TDHNEYS.

Patented June4, 1940' UNITED: STATES PATENT OFFICE 3 Claims.

Thislnvention relates to improvements inexpanding tools and has particular reference to a piston expanding tool for expanding and treating worn motor vehicle pistons.

The principal object of the present invention is to provide a piston expanding or rec'onditioning tool and a unique process or method of applying the tool, whereby a successful and positive expanding treatment may be applied to worn motor vehicle pistons.

Another object of the invention is to provide a tool of the character set forth whichv is especially adapted to the treatment or reconditioning of alloy pistons and'one which when inserted in a piston and properly expanded will hold the piston skirt in its adjusted or expanded position while being heated.

A further object of the invention is to provide an expanding tool of this character-which when inserted in position and expanded will not cause distortion of the wrist pin bosses as it straddles the wrist pin, which pin is left in the piston during the entire expanding operation.

A still further object of the invention is to provide a tool which is positive in its action, may be easily inserted into a piston to be treated, and is comparatively simple in design and, therefore, may be economically constructed.

Other objects and advantages will be apparent during the course of the following description.

In the accompanying drawingsforming a part of this specification and in which like numerals are employed to designate like parts throughout the same:

Fig. 1 is a side elevation of theimproved ex.- panding tool, showing the operating parts thereof in normal position; I

Fig. 2 is a side elevation of the tool shown in operative position in'a piston to be expanded;

Fig. 3 is an end view of the tool;

Fig. 4 is a plan section of the tool taken on the line 4--4 of Fig. 2 and further illustrating the operating elements of the device;

Fig. 5 is a side elevation partly in section, showing the expanding elements of the tool swung outwardly to better illustrate the operation thereof;

Fig, 6 is a full scale elevation of the tool partly in section, showing all operating elements in normal or non-expanded positions;

Fig. 7 is a plan view of a piston, showing a modified form applied to the wrist pin bosses of the piston;

Fig. 8 is a plan view of a piston having plates inserted therein to engage the expanding tool diameter to fit the tool.

It is a well-known fact in the art of repairing motor vehicle engines that used pistons are much better than new ones for various reasons, one reason of importance being that pistons which have operated in an engine for a considerable period become tempered and seasoned, and another important fact being that these worn pistons may be much more cheaply repaired and refitted in the engine cylinders than new pistons which haveto be turned and precisely fitted in the engine, which requires more time and expense than that required in reconditioning the worn pistons.

Figs. 1 to 6 inclusive illustrate the preferred form of the invention and include an expander plate It having pivotally mounted at opposite lower edges links H and I2, which links are in turn pivoted to links I 3 and M at the points l5 and I6 respectively.

One end of the plate It is provided with a threaded stud 11, upon which is loosely mounted has a threaded end 24 adapted to engage the threads of said stem, the threaded end of said tube normally bearing against the face of the bevelled disc 2|, and said tube being provided at its upper end with an operating handle 25.

The links i I and I2 are provided with integrally formed expanding bars 25 and 27 respectively, and the links I3 and I4 are provided with similar transversely arranged expanding bars 28 and 29 respectively, said links II and I2 also being provided with cam elements 30 and Si fixed thereto and having obliquely arranged cam faces capable of engaging opposite bevelled faces of the disc l8, and the links l3 and I4 are each provided with similar obliquely arranged cam faces 32 and 33 respectively capable of engaging opposite bevelled faces of the disc 2|.

It will now be observed that when the tool is to be inserted into the skirt section of a piston 35 to be expanded, the wrist pin 36 must be first removed from the piston bosses. The tool is next placed within the skirt in a normal collapsed position, and the wrist pin is again replaced in the piston bosses and extends through the aligned opening 31 formed in the plate H) to receive the tool. The links H, I2, l3, and M, of course, straddle the wrist pin 36 of the piston.

In Fig, 7 I have shown a modified form in which a threaded member 38 may be inserted in the piston bosses and is provided with threaded nuts 39 and Gil which may be rotated upon the threaded member 38 by means of any suitable tool.

Fig. 8 is a plan view of a pistonwhich may be too large in diameter to effectively receive the tool. Therefore, I provide insert plates 4| and 2 to reduce the inner diameter of the piston skirt between which the operating elements of the tool may be operated to properly expand the piston skirt.

It will now be observed that when the tool is inserted into a piston to be reconditioned, the links are all necessarily in retracted positions and when properly set by the reinsertion of the wrist pin are expanded in the following manner:

The handle 22 is rotated, which causes the rotation of the stem 20, said stem, carrying the threaded sleeve l9, causes the sleeve to bear downwardly and force the beveled disc downwardly and against the cam members 30 and 3|, thus forcing the links H and I2 outwardly and causing theexpanding bars 26 and 21 to likewise move outwardly and firmly grip and ex pand the inner walls of the piston.

When the operating handle 25 is operated, the tube 23, carrying the nut 2d, moves downwardly upon the threaded stem. 20 and forces the bevelled disc 2| downwardly, which disc rides against the oblique cam sections 32 and 33 of the links l3 and It, which action causes these links to be expanded and force the expanding bars 28 and 29 outwardly against the interior wall of the cylinder skirt, this expanding action, of course, being determined by the conditions required.

The tool is now locked in position in the piston, and the piston and tool are next placed in a heating oven and heated to the desired degree, and the tool and piston are then placed in a solution and chilled; and if the proper degree of expansion is not acquired after tests, this operation is repeated until the piston is expanded to a precise fit in the engine cylinder.

. It is to be understood that the form of my in vention herewith shown. and' described is to be taken as a preferred example of the same and that various changes relative to the material, size, shape and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

Having thus described my invention, I claim:

1. A tool of the class described embodying expansible cooperating pairs of links carrying piston expanding bars arranged in pairs, one above the other, means associated with said tool for expanding said links, said means including cam elements formed on said links, and threaded adjusting elements cooperating with said links and carrying bevelled members capable of contacting said cam elements, said threaded elements being arranged to selectively operate said bevelled members, whereby the piston expanding links and bars may be selectively expanded to engage the interior wall of the piston skirt at different points relative to the end thereof.

2. In a tool of the class described including a plate having a threaded stud formed on one end thereof, expansible cooperating links pivoted to one end of said plate, said links havin cam elements formed thereon, a bevelled operating disc freely mounted on said stud and capable of engaging the cam elements of certain of said links, a threaded stem having an integrally threaded sleeve normally engaging said stud to cause the actuation of said operating disc,

a second set of links pivoted to the first mentioned links and having cam faces, a second bevelled operating disc loosely mounted on said threaded stem and capable of engaging the cam. faces of the second set of links, and a tubular member surrounding said stem and having a threaded end section engaging the threaded stem and normally contacting said second-mentioned operating disc, whereby when said threaded stem and said tubular member are rotated, the link members are independently expanded.

3. In a tool of the class described. including a plate having a threaded stud formed on one end thereof, expansible cooperating links pivoted to one end of said plate, said links having cam elements formed thereon, a bevelled operating disc freely mounted on said stud and capable of engaging the cam elements of certain of said links, a threaded stem having an integrally threaded sleeve normally engaging said stud to cause the actuation of said operating disc a second set of links pivoted to the first mentioned links and having cam faces, a second bevelled operating disc loosely mounted on said threaded stem and capable of engaging the cam faces of the second 

